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dnxhd_parser.c
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1 /*
2  * DNxHD/VC-3 parser
3  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * DNxHD/VC-3 parser
25  */
26 
27 #include "parser.h"
28 
29 #define DNXHD_HEADER_PREFIX 0x000002800100
30 
31 typedef struct {
34  int cur_field; /* first field is 0, second is 1 */
36 
38  const uint8_t *buf, int buf_size)
39 {
40  ParseContext *pc = &dctx->pc;
41  uint64_t state = pc->state64;
42  int pic_found = pc->frame_start_found;
43  int i = 0;
44  int interlaced = dctx->interlaced;
45  int cur_field = dctx->cur_field;
46 
47  if (!pic_found) {
48  for (i = 0; i < buf_size; i++) {
49  state = (state<<8) | buf[i];
50  if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {
51  i++;
52  pic_found = 1;
53  interlaced = (state&2)>>1; /* byte following the 5-byte header prefix */
54  cur_field = state&1;
55  break;
56  }
57  }
58  }
59 
60  if (pic_found) {
61  if (!buf_size) /* EOF considered as end of frame */
62  return 0;
63  for (; i < buf_size; i++) {
64  state = (state<<8) | buf[i];
65  if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {
66  if (!interlaced || dctx->cur_field) {
67  pc->frame_start_found = 0;
68  pc->state64 = -1;
69  dctx->interlaced = interlaced;
70  dctx->cur_field = 0;
71  return i-5;
72  } else {
73  /* continue, to get the second field */
74  dctx->interlaced = interlaced = (state&2)>>1;
75  dctx->cur_field = cur_field = state&1;
76  }
77  }
78  }
79  }
80  pc->frame_start_found = pic_found;
81  pc->state64 = state;
82  dctx->interlaced = interlaced;
83  dctx->cur_field = cur_field;
84  return END_NOT_FOUND;
85 }
86 
88  AVCodecContext *avctx,
89  const uint8_t **poutbuf, int *poutbuf_size,
90  const uint8_t *buf, int buf_size)
91 {
92  DNXHDParserContext *dctx = s->priv_data;
93  ParseContext *pc = &dctx->pc;
94  int next;
95 
97  next = buf_size;
98  } else {
99  next = dnxhd_find_frame_end(dctx, buf, buf_size);
100  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
101  *poutbuf = NULL;
102  *poutbuf_size = 0;
103  return buf_size;
104  }
105  }
106  *poutbuf = buf;
107  *poutbuf_size = buf_size;
108  return next;
109 }
110 
113  .priv_data_size = sizeof(DNXHDParserContext),
114  .parser_parse = dnxhd_parse,
115  .parser_close = ff_parse_close,
116 };